Process of treating cellulosic material



Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE PROCESS OF TREATINGCELLULOSIC MATERIAL Eulampiu Slatineanu, Oberhausen, Germany, as-

signor to Gewerkschaft Auguste, Oberhausen, Germany, a company ofGermany No Drawing. Application February 20, 1937, Serial No. 126,837.In Germany April 26, 1935 able products and more especially hydrocarbonsfrom cellulosic material, such as cellulose 01' any kind, cotton andwood or woody or ligneous materials, or derivatives of cellulose andlike substances.

My invention has particular reference to the production of valuablecompounds from carbonaceous materials by the action, at an elevatedtemperature and under high pressure, of methane.

My invention is based on the discovery that dipol-free molecules,whenacted upon by high pressure, 1. e. when the electron shells arecompressed, can be polarized, so that under sufliciently high pressurethe methane molecule, in contrast to all that could be expected, is nolonger an indifferent, but a highly reactive compound. In principle theprocess according to my invention thus consists in that methane or agas, mixture which contains methane islcaused to act upon cellulosiematerial such as cellulose of any kind, cotton and wood or woody orjligneous materials, or derivatives of cellulose andliiike substances,under a pressure which is suiilcient' to cause a polarization of themethane present inamounts as a rule to 500 atmospheres as a minimum. If,however, ethylene or acetylene or a" mixture of ethylene and acetyleneis present in the gas mixture in a quantity amounting to about 20 percent or more by volume, a pressure of about 250 atmospheres may besufflcient to render the methane highly reactive in the sense explainedabove. I have ascertained that under the action of this high pressurethe methane will not only prevent CH4 from being split on from thecompounds treated, but will even cause CH4 to combine with the startingmaterial or with the fragments, into which these materials are split,condensation taking place simultaneously in certain cases. Thiscombination may also occur with simultaneously a splitting of the carbonchain. In many cases I prefer to choose the partial pressure of themethane far higher than the 12 Claims. (or. 260466) sum of the partialpressures of the gaseous compounds reacted with it.

In contradistinction to prior art processes a reaction temperature of390 C. need not be overstepped, whereby the control of the opera- 5 tionis facilitated and the apparatus rendered simpler and less expensive.

The temperature limit, above which the desired reactions do not proceedany more with satisfactory yield, can be determined by means of thethermodynamic formulae oi the free energies calculated for instanceaccording to the method of Lewis and Randall.- The notation used bythese authors, for instance in Thermodynamics" (as published in 1923 byMcGraw and Hill) will 18 I be used herein. In certain cases, defined bythe well known phase rule, the same is true of the limits oi themolecular proportions of the reacting materials. I have found itadvantageous as far as the yield is concerned, to determine the 20.reaction temperature and the molecular propor- (D here stands for A.)BF corresponds to a figure ranging between a: and +5000 goal.

I1 R. is the gas constant, T the absolute temperature, ln Napierslogarithm, K the equllibrium constant, the formula, if Briggs logarithmis used, will be -4.5753T.log K=2F From the constant K the totalpressure can be computed according to the law of mass action as the sumof the partial pressures of the components of the equilibrium.

From the formula there thus results that the partial pressures of thecomponents formed and simultaneously the yield rise, as the partialpressure of the methane rises. The rising pressure of the methane alsofavors the conversion of the free carbon, which may be present, into anonsolid phase.

The reaction may also be furthered and accelerated by adding suitablecatalysts. However, in view of the high pressure the presence ofcatalysts is not necessary.

if the process is for instance applied to un- However the reaction mayalso be so conducted that at the same time the starting material,orconstituents of the same, is or are split up into lower molecularcompounds, for instance according to the equation Compounds containingoxygen also add methane and according to the starting material and tothe conditions of operation water may separate and a furthercondensation may take place, for instance according to the equation orthe starting material may be split into lower molecular compounds, forinstance according to the equation Instead of methane also gas mixturescontaining methane may be used; obviously the partial pressure of themethane in the system must be kept correspondingly high.

If the methane or the gas mixture containing same also contains about20% by volume or more ethylene or acetylene or a mixture of ethylene andacetylene, the operation may also be carried through under a pressure ofless than 500 and sometimes even down to 250 atmospheres. For similarlyas carbon monoxide (CO) such unsaturated hydrocarbons are unstablemolecules and the reaction is therefore not only stimulated by thepressure, but also by the potential energy of the unsaturated molecules.

In many cases it has been found advantageous to cause the reaction totake place in a heterogeneous system, i. e. in such manner that at leastone of the reaction components already present or the final productsformed remains liquid under the operating pressure.

The cleavage products (fragments) such-as methane and its homologues,hydrogen, ethylene and its homologues, carbon monoxide, acetylene andits homologues, naphthalene, other tar constituentsand solid carbon,which are formed in the hitherto known processes of conversion ofcarbonaceous materials, are not stable under the conditions of operationof the present. process, but will react according to the followingequations with the formation of liquid hydrocarbons:

In these equations only representatives of the different groups(paraflins, oleflnes, acetylene, naphthenes, naphthalenes etc.) areshown. The reactions will occur in a similar manner with theirhomologues or derivatives. Obviously, each of these reactions can becarried out singly or a plurality of such reactions may be carriedthrough in combination.

According to the laws of thermodynamicscarbon may be formed in differentways when carrying through these processes. It need not be separatedfrom a solid phase, but may alsobe formed for instance from carbonmonoxide according to the equation:

2CO=CO2+C If the gaseous phase contains hydrogen, the

' equilibrium may also play a role.

Under the operating conditions the carbon thus separated will react withthe higher molecular carbon compounds and also with the methane. Ifcarbon monoxide and hydrogen are present, the new process may also beexplained thermodynamically in such manner that primarily the reactionoccurs and that thereafter the alcohol reacts with methane alone or withhigher. molecular organic carbon compounds and methane for instanceaccording to the equation:

These theoretical considerations were subjected to practical laboratorytests and it was found that under the conditions of'this inventionalcohills of any kind will in fact react with methane alone'or withhigher molecular organic carbon compounds and methane for instance asfollows Unsaturated hydrocarbons also have the tendency of separatingcarbon from the gaseous phase, for instance as follows:

In view of thermodynamic calculations the reaction between carbonmonoxide and methane may also proceed by way of ethylene as follows Theethylene will then however be decomposed again according to the Equationa. Consequently in this or similar reactions special provision must bemade for preventing the separation of carbon.

This separation can be prevented by any one of the following steps:

These two steps may also be used incombination in order to prevent theseparation of carbon. In this case the system contains a liquid phase,and the partial pressure of the methane exceeds by far the sum of thepartial pressures of the gaseous components to be reactedvwlth methane.

For thermodynamic reasons carbon does not react with methane directlyfrom a solid phase.

It has already been pointed out farther above that the reactions proceedmore readily, more completely, and in a more easily regulatable manner,if at least one liquid phase is present. Therefore one of theequilibrium componentseither of the starting materials or of theproducts formed in the reactionshall be liquid under the conditions ofreaction. In the reactions mentioned above water will always appear as acomponent, since the plurality of these reactions proceed below thecritical point of water, and therefore the liquid phase is here alreadypresent in the form of water. One may however also provide the liquidphase by injecting into the reaction chamber, besides the reactioncomponents to be reacted in the first place also substances which remainliquid under the reaction conditions, such as for instance paraffines,paraffine oil, vaselines, tar oils, etc. This addition is particularlyuseful in the case of reaction components having a tendency to separateout low molecular parafiines. In such case heavier paraffines added tothe mixture will react with the light paraflines formed and will acttowards carrying the reaction to completion within a technicallyadmissible period of reaction.

In practising this invention one may proceed for instance as follows:

Example 1 'Ewample 2 Wood meal is mixed with a high-boiling oil such asgas oil or creosote oil. The pasty mass is treated in an autoclave at360 C. under a pressure of 1800 atm. with methane in the presence of acatalyst consisting for instance of iron molybdate. There are formedbenzine-lilre hydrocarbons and water. The wood is almost completelyconverted into hydrocarbons; from 1000 parts by weight dry woodsubstance 1050 parts by weight hydrocarbons and 400 parts water areobtained- The process may be carried through in an apparatus of the kindused for high pressure reactions, for instance in a hydrogenationapparatus as used in the Bergius-process.

Various changes may be made in the details disclosed in the foregoingspecification without departing from the invention or sacrificing theadvantages thereof.

I claim:

v1. The process of producing hydrocarbons from cellulosic material,which comprises acting upon such material in the presence of a liquidphase at an elevated temperature not exceeding 390 C. with a gasmixture, which contains a substantial proportion of methane, under atotal pressure of at least 500 atmospheres above normal and a partialpressure of methane which suflices to cause a polarization of themethane present.

2. The process of claim 1, in which the maphase at an elevatedtemperature not exceeding- 390 C. with a gas mixture, which contains asubstantial proportion of methane, under so high a pressure that thepartial pressure of the methane amounts to at least 500 atmospheres.

7. The process of claim 1, in which the treatment is effected in aheterogeneous system, at least one liquid phase participating in thereaction.

8. The process of claim 1, in which the treatment is effected in aheterogeneous system, at least one liquid phase being formed by an addedsubstance which is liquid under the conditions of the reaction.

9. The process of claim 1, in which the partial pressure of the methaneis chosen far higher than the sum of thepartial pressures of the gaseouscompounds reacted with it.

10. The process of producing hydrocarbons from cellulosic material,which comprises acting upon such material in the presence of a liquidphase at an elevated temperature not exceeding 390 C. with a gasmixture, which contains a substantial proportion of methane and morethan 2.0 per cent by volume ethylene, under a pressure of at least 250atmospheres which suflices to cause a polarization of the methanepresent.

11. The process of producing hydrocarbons from cellulosic material,which comprises acting upon such material in the presence of a liquidphase at an elevated temperature not exceeding 390 C. with a gasmixture, which contains a substantial proportion of methane and morethan 20 per cent by volume acetylene, under a pressure of at least 250atmospheres which sufllces to cause a polarization of the methanepresent.

12. The process of producing hydrocarbons from cellulosic material,which comprises acting upon such material in the presence of a liquidphase at an elevated temperature not exceeding 390 C. with a gasmixture, which contains a substantial proportion of methane and morethan 20 per cent by volume ethylene and acetylone, under a pressure ofat least 250 atmospheres which suf'fices to cause a polarization of themethane present.

EULAMPIU SLA'I'INEANU.

iii)

